Bug 2358219 (CVE-2025-22010)

Summary: CVE-2025-22010 kernel: RDMA/hns: Fix soft lockup during bt pages loop
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-04-08 09:01:22 UTC
In the Linux kernel, the following vulnerability has been resolved:

RDMA/hns: Fix soft lockup during bt pages loop

Driver runs a for-loop when allocating bt pages and mapping them with
buffer pages. When a large buffer (e.g. MR over 100GB) is being allocated,
it may require a considerable loop count. This will lead to soft lockup:

        watchdog: BUG: soft lockup - CPU#27 stuck for 22s!
        ...
        Call trace:
         hem_list_alloc_mid_bt+0x124/0x394 [hns_roce_hw_v2]
         hns_roce_hem_list_request+0xf8/0x160 [hns_roce_hw_v2]
         hns_roce_mtr_create+0x2e4/0x360 [hns_roce_hw_v2]
         alloc_mr_pbl+0xd4/0x17c [hns_roce_hw_v2]
         hns_roce_reg_user_mr+0xf8/0x190 [hns_roce_hw_v2]
         ib_uverbs_reg_mr+0x118/0x290

        watchdog: BUG: soft lockup - CPU#35 stuck for 23s!
        ...
        Call trace:
         hns_roce_hem_list_find_mtt+0x7c/0xb0 [hns_roce_hw_v2]
         mtr_map_bufs+0xc4/0x204 [hns_roce_hw_v2]
         hns_roce_mtr_create+0x31c/0x3c4 [hns_roce_hw_v2]
         alloc_mr_pbl+0xb0/0x160 [hns_roce_hw_v2]
         hns_roce_reg_user_mr+0x108/0x1c0 [hns_roce_hw_v2]
         ib_uverbs_reg_mr+0x120/0x2bc

Add a cond_resched() to fix soft lockup during these loops. In order not
to affect the allocation performance of normal-size buffer, set the loop
count of a 100GB MR as the threshold to call cond_resched().